Three(four) Metal52 or Grove52 linked together

Hi,

we have a setup where there are two sailboats and one(maybe two) coach boat that needs wifi connection.
Each sailboat will have its own router with 4G internett connection, coachboat will have a switch to connect a computer and then use a wireless screen.

Will it be possible to use Metal52 or Grove52 as AP(or similar) and connect all together on the same network?
The Metal52 or Grove52 should also be used as range extender onboard for iPad on deck.

We can setup different gateways so that each sailboat uses its own 4G network.
Range we are looking for is as “good as possible”, a range of 400-500 meters would be great.
Its just two text strings sent on UDP every second so speed is not a concern, no HDTV streaming.
Have had a look at the Unifi AC mesh, but it looks like Metal52 or Grove52 will have a greater range.

Martin